Piston



Dec. 8, 1931.

F. JARDINE ET AL 1,835,874

PISTON Filed Jan. 6, 1926 2 SheetS -Sheet 1 Invenfors Dec. 8, 1931. F. JARDINE ET AL PISTON 2 Sheets-Sheet 2 Filed Jan. 6, 1926 ,jwuewiioz S w M 61cm naq s Patented Dec. 8, 1931 UNITED STATES PATENT-OFFICE FRANK JABDINE AND JAMES GOOIPJElIt, OE CLEVELAND, OHIO, ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE CLEVELAND TRUST COMPANY, OF CLEVELAND, OHIO, A

CORPORATION OF OHIO, AS TRUSTEE rIsToN Application filed January This invention relates to pistons for in-' Frank J ardin'e, Serial No. 47,214, filed July It is well known that such pistons possess many desirable qualities such as lightness, high heat conductivity and the like, but since the co-eflicient of expansion due to heat of such materials differs from that of the cylinders in which they operate, difliculties and disadvantages are encountered at various temperatures, for example, pistons that will not slap when cold will stick when hot, and

vice versa. v

The principal object of our invention is to provide a piston made of aluminum, aluminum alloy, or the like, which can be fitted with a very small clearance when installed and which clearance will be substantially maintained throughout the temperature ranges met in practice, Without slapping,

binding or scoring of the cylinder or unduewear on the piston itself.

These and other objects of our invention as well as the invention itself will be better understood from a description of one or more structures embodying the invention.

In the drawings forming a part of this specifi'cation Fig. 1 is a side elevation of a piston embodying our invention;

Fig. 2 is a section thereof along the line 22 of Fig. 1;

Fig. 3 is a bottom plan view thereof;

Fig. 4 is an elevation of the member A hereinafter to be particularly described;

Figs. 5, 6 and 8 are views of a second pis- 6, 1926. Serial N0. 79,651.

ton embodying our invention corresponding to Figs. 1, 2 and 4; and i Fig. 7 is a transverse sectional View taken on line 7-7 of Fig. 5.

We will refer first to the embodiment illustrated in Figs. 1 to 4, inclusive. The head of the piston is shown at 9 and consists of the top 10 and side walls 11 grooved at 12 for the piston rings. The walls 11 are shown as cylindrical. As many grooves 12 as desired may be used. The piston skirt is shown generally at 13 and comprises thrust or wear face parts 14 and 15. The part 14 is connected directly to the head,preferably it is integral with the head as illustrated in the drawings. The part 15 is, however, separated from the head by an air gap 16 here shown as a horizontal slot cut between the side wall of the head 11 and the part 15 and running parallel to the grooves 12. The piston is provided with bosses 17 and 18 for the wrist pin. These bosses are located in alignment and diametrically opposite one another in the piston. The bosses are connected tothe head by members, here shown as webs 19., '20, 21

and another like 20, but not illustrated in the I drawings. These webs are parallel with the wrist pin axis and-serve to make the piston stauncher as well as to connect the bosses to the head. The bosses should be, and are best, connected so that the head, skirt and bosses are integral and of the same material as the bottom of the skirt. In the embodiments shown, this is accomplished by .the web's 22 and 23 which are connected. the under sides of the bosses and to the inner sidesof the skirt through members 24? and 25 here shown as culvert-shaped an hereinafter called culverts. The piston head is preferably strengthened by webs 26. {The skirt is cut away as shown at 27 and, 28 about'the bosses 17 and 18 and the bosses are set within the perimeter of the piston to permit expansion along the axis of the wrist pins without binding or scoring.

The piston skirt is best 'made continuous below the openings 27 and 28. In the embodiments shown, strap-like members 29 and 30 connect the parts 14 and 15' at theibottom- The member 29 is slitted along the long axis part. 15 in much the same manner.

of the piston at 31 and the member 30 is slitted likewise at 32. These slits are preferably slanting to the long axis'of the piston and are spanned by the culverts 24 and 25 which are of resilientmateri'al. The piston skirt thrust parts 14 and 15 areconnected together by members of a material having a lower co-efficient of expansion than aluminum'such as steel or iron, which regulate the expansion of the skirt to maintain the expansion thereof constant with the expansion of the engine cylinder, or so nearly thereto, that though there is very little clearance at the time the pistons are installed, such clearance is substantially maintained and there will be no slap, no sticking and no scoring or undue wear.

In the embodiment shown, strips of the desired material are used to interconnect the parts of the skirt. Thesestrips are anchored in the parts they connect. It is convenient to use such members as A, (Fig. 4) which are best made of iron, steel or other suitable materialand which consist of the lateral members 33 and 34 and the vertical members 35 and 36 provided with catches37. To securely connect the members 33 and 34 to the skirt parts the vertical members 36 may be buried in the part 14, for example, by embedding them in buttresses formed on the inside wall. of the part 14, thus securely anchoring the. ends of the lateral members 33 and 34 in thepart 14. The other ends of the members 33 and 34 are as securely anchored in the face The vertical members 35 are buried in the buttresses 39 formed on the inner walls of the part 15 of I v the piston skirt. 7 The bosses 17 and 18 and webs 1 9, 20 and 21 are opened at 40 and 41 and 42 and 43, respectively, to permit the passage of themembers 33 and 34 and to permit such members to slide slightly therein during the expansion and contraction of the skirt. As will be seen the members 33 and 34 are arranged chordally in the piston.

' By connecting the piston skirt thrust face parts together with both iron and aluminum, we avoid slapping at the. high temperatures and dangerof cocking of the member 15 out of normal dfie to unequal heating and conseqlliifnt expansion at the top and bottom ofthe There will also be no danger of the member 15. cocking out of line since the more rapidly expanding aluminum steel combination at the bottom will compensate for lower tem-' peratures there. Nor will there be danger of binding at the bottom of the piston skirt when the circumference of the skirt is complete, since the slits 31 and 32 permit circumferential expansion and the resilient culverts will insure the expansion into these slits instead of outward and away from them. For

while the parts 24. and 25 ofthe culverts expand giving the required expansion perpendicular tothe wrist pin axis, circumfer- Asthe. piston heats, the bossestend move outward, for which movement there is ample allowance. The expansion in the other direction will be from the member 14 and will be the resultant expansion of the members 7 33,34, 24 and 25, and of course the expansion of the thrust faces, and these parts are so regulated that the piston walls will follow the cylinder walls with fidelity. Contraction Wlll be in reverse of expansion.

In the embodiment shown in Figs. 5 inclusive, connectors 50 and 51 are substi tuted for the culverts. In this embodiment, the aluminum expansion parallel to the members 33 and 34 is.achieved by thebottoms 52 of the bosses l'Z and-18.

It will be seen that although we make our 1 piston of acontinuous, infact, in the embodiments illustrated, an integralipiece of aluminum or the like, we do not shackle or loop the skirt withiron bands or the like, nor

do We separate or isolate the partsone from the other, but employ aluminum and iron parts in such arrangements that we elimiate from-the pistons the faults and vices of the prior iron and aluminum pistons. The term aluminum used herein is broad enough to include aluminum alloys.

The piston is very staunch and is easily machined. The heat ise-ffectively conducted from the head especially where the thrust face 14 joins the head. The members A are relatively light and more securely anchored in the thrust walls. The explosion load is preferably taken on the face 14, -which is inte ral with the head, and the inertia load on the ace15.

The pistons may be, and preferably are,- relievedas shown at 60 in; Figs. 1, 3, 5 and 7 to enhance the realization of the advantages already recited herein.-

While we have illustrated anddescribed these embodiments of our invention and these particular details, we wish to be limited neither to these embodiments nor the details thereof, since many departures from both may be made-without departing from the spirit of the invention.

1. In a piston having a skirt made of ma terial having a relatively high co-efiicient of expansion comprising thrust members, one of which'is connected to the head at the periphery and separated from each other by open spaces running from near the top of the pis-' ton to near the bottom of the skirt and extending on both sides of the bosses, but leaving the continuity of the piston uninterrupte ed at the bottom and means of a material of a lower co-efiicient of expansion than the material of the skirt bridging said open spaces and connecting said thrust members together.

2. In an aluminum alloy piston, a skirt having thrust members one of which is connected to the head at the periphery and being connected together at the top by steel only and at the bottom by aluminum and steel.

3. In a piston for internal combustion engines or the like, the combination of a head having a depending flange grooved for piston rings and a skirt, both head and skirt composed of a material having a relatively high co-eflicient of expansion, said skirt having diametrically opposite thrust faces, one of which is connected to the head but the other of which is disconnected from the head by an arcuate air gap, said thrustv faces-being separated from near the top to near the bottom of the skirt but leavingv the bottom of the skirt connected for a ways, up from the bottom, wrist pin bosses set within the periph- I cry of the skirt, connecting means connecting said thrust faces together made of a material having a lower co-eflicient of expansion than the skirt and extending chordally from one face to the otherperpendicular or substantially perpendicular tothe wrist pin axis both above and belowthe axis, the portions of the skirt below the bosses being slitted and culvert-like'members on the in-. side of the skirt spanning said slits.

4. In apiston, a skirt made of a material having a relatively high co-efiicient of expansion and including a skirt comprising thrust face members one of which is connected to the head at the periphery and separated from near the top to near the bottom, means of a relatively low co-eflicient of expansion material connecting said thrust face members, the unseparated portions of the skirt being slitted and culvert-like members spanning said slits.

5. In an aluminum alloy piston, a skirt'having thrust faces, one of which is connected directly to the head and said thrustfaces being connected at the top by steel alone and connected at the bottom with steel and aluminum and having pin bosses set within the perimeter of the piston, said skirt being cut away or relieved in the regions of the bosses.

6. In a piston, the combination of a head and a skirt having thrust faces made of a material having a relatively high co-eflicient of expansion,one of said thrust faces being integral with the head and the other being separated from the head and connectors of a material having a lower co-eflicient of expansion than the material of the skirt anchored at either end in one of said thrust faces and extending across the piston and connected to thebosses.

7. In a piston for internal combustion enmeans may reciprocate.

gines or the like, the combination of a head consisting of atop and a depending cylindrical shaped flange grooved on the outside for piston rings, a skirt for the piston comprising portions having thrust faces adapted to engage the walls of the cylinder of the engine when the piston is mounted therein, said skirt being generally cylindrical in shape and said skirt and head being made of. a material-havdiametrically oppositely placed wrist pin bosses mounted in said skirt and having their outer ends within the periphery of the skirt,

means connecting said wrist pinbosses with mg a relatively high co-efficie'nt of expansion,

head to below the bosses and leaving the lower portion of the piston connected together circumferentially, the lower portions of the 'pistons being slit below the bosses, culvertshaped members of the same material as the skirt mounted within the piston and spanning said slits, one of said thrust face portions of the pistombeing integral with the head and the diametrically opposite thrust face portion being disconnected from the head by an arc-uate slot at the top of said thrust face portion, connectors made'of a material of a relatively lower coefficient of expansion than the ma terial of the piston anchored 'at either end in the thrust faces and passing through the bosses in the central portions thereof, one of said connectors being located above and one below each boss and each extending on a chord across the interior of the piston nd perpendicular or substantially perpendicular to the wrist pin axis. 4-

8. In a piston, the combination of a pair of diametrically oppositethrust face members of high expandible material one of which is connected to the head at the periphery, wrist pin bosses and connectors of low expandible material slidably mounted in said bosses and connecting said face members together.

9. In a piston for internal combustion engines, the combination of a head and skirt composed of a plurality of parts, one of which is attached to andanother of which is detached from thehead and a tie slidably mounted in the pistonv interconnecting said parts.

10. In a piston for internal combustion engines, the combination of a head and a skirt comprising two thrust-face portions, one of which is connected to the head and the other of which is disconnected from the head at the top, means in said piston intermediate said portions and interconnecting'ties joining said portions and having hearings in said intermediate means in which such interconnecting 11. In a piston for an internal combustion engine, the combination of a head and a skirt comprising two thrust face portions, one of ofwhich is disconnected from the head by a slot at the top, said portions being separated partway along, interconnecting means for oining saidportions together and wrist pin bosses provided with openings through which said interconnecting means may move back and forth.

12. In a piston for'an internal combustion I engine, thecombination of a head and a skirt comprising two thrust face portions, one of which is integral with the head and the other ofwhich is disconnected'from the head by an air gap, said portions being separated part way. and slit't'ed the rest of the way with bridges connecting them across theslits, and

' interconnecting means joining the thrust face bosses and connectors of low expandible maportions over the separated parts, composed of a material having a lower co-eflicient ofex- I 6 pansion than the materialof the piston and intermediate members including wrist pin bosses provided with openings through which said interconnecting means may reciprocate.

13. In a piston, the combination of a pair of diametrically op osite thrust face members of'high expan 1ble material, wrist pin terialslidably mounted in said bosses and connecting said face members together.

' 14. In a piston for internal combustion engines, the combination of a head and skirt composed of a plurality of parts, one of which is detached from the head and means slidainterconnecting means for joining said por-' tions together and wrist pin bosses provided with openings through which said interconnecting means may move back and forth.

17. In a piston for an internal combustion engine, the combination of ahead and a skirt comprising two thrust. face portions, said portions being separated part way and slitted v the rest of the way with bridges connecting them across the slits, and interconnecting means oimng the thrust face portions over the separated parts, composed of a material having a lower co-efiicient of expansion than the material of the piston and intermediate members including wrist pinbosses provided.

ton for internal combustion en- 7 signatures this 28th skirt comprising two thrust face portions, one of which is separated from the head, said portions being separated part way along, interconnecting means for joining said portions together and wrist pin bosses provided with openings through which said interconnecting means may move back and; forth.

19. In a piston for an internal combustion engine, the combination of a head and skirt including spaced thrust face portions, the explosion thrust face portion being connected to the head and the compression thrust face portion being disconnected from the head, wrist pin bossesand means including metals of different coeflicients of heat expansion connecting the bosses to the thrust faces so as to resist the relative expansion and contraction between the faces and the wrist pin bosses. I

20. In a piston for an internal combustion engine, the combination of a head and skirt including thrust face portions, one of which is connected to the head and one of which is separated from the head, means of a lower co-efiicient of heat expansion than the material of the piston tying said thrust faces together,-and means of the same material as the piston joining said thrust faces together, said piston being relieved between the thrust faces.

on the eri her P P X 5 21. In an aluminum alloy.piston,the combination of a head, a skirt having thrust members one of which is connected to the head at the periphery, steel means constituting the sole connect-ion between the top .part

of the thrust members and steel and yieldable aluminum members connecting the bottom part of'the thrust members together, piston pin. bosses and means connecting the bosses to the bottom part of the skirt.

In testimony whereof we hereunto aflix our day of December, 1925.

JAMES COOPER. FRANKv JARDI'NE with openings through which said interconnecting means may move back and forth.

18;. In a piston for an internal combustion engine, the combination of a head and a 

